Able to calculate neater form including hesitation (8)
I believe the answer is:
numerate
'able to calculate' is the definition.
(I've seen this before)
'neater form including hesitation' is the wordplay.
'form' indicates anagramming the letters (a different form of the same letters).
'including' indicates putting letters inside.
'hesitation' becomes 'um' (sound made when hesitating).
'neater' anagrammed gives 'nerate'.
'nerate' going around 'um' is 'NUMERATE'.
(Other definitions for numerate that I've seen before include "Well versed in maths" , "Capable of understanding mathematics" , "Good at maths and science" , "Able to count, work with figures" , "Able to calculate" .)